<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <link rel="stylesheet" href="style.css">
    <style>
        .box{
            width:600px; height:600px;
            background: pink;
        }
        .box div{
            width: 300px; height:300px; background: red;
            /* display: none; */
            visibility: hidden;
        }
        .box:hover div{
            visibility: visible;
        }
        /* 
          display: none; 隐藏 原来的位置消失，不占位
          visibility: hidden; 隐藏 原来的位置会被保留，占位的
          visibility: visible;不隐藏 （可见）


             显示隐藏
                1，display:none;
                2, opacity
                3, height:0; overflow:hidden;
                4, visibility: hidden
        */
    </style>
</head>
<body>
    <div class="box">
        <div></div>
    <p>
        ,==========, 
        |   |  |   | 
        `-./    \.-' 
           `.__.' </p>
        </div>
</body>
</html>